In November of 1919, at the age of 40, Albert Einstein became an overnight celebrity, thanks to a solar eclipse. An experiment had confirmed that light rays from distant stars were deflected by the gravity of the sun in just the amount he had predicted in his theory of gravity, general relativity. General relativity was the first major new theory of gravity since Isaac Newton's more than 250 years earlier.
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Gravity

"General relativity proposed that gravity, as well as motion, can affect the intervals of time and of space."
"Gravity pulling in one direction is completely equivalent to an acceleration in the opposite direction."
"If gravity is equivalent to acceleration, and if motion affects measurements of time and space (as shown in special relativity), then it follows that gravity does so as well."
"Bending of starlight by gravity and a tiny shift in the orbit of the planet Mercury, have been quantitatively confirmed by experiment. Two of the strangest predictions, impossible ever to completely confirm, are the existence of black holes and the effect of gravity on the universe as a whole (cosmology)."

Collapsed Stars (Cosmology)
"A black hole is a region of space whose attractive gravitational force is so intense that no matter, light, or communication of any kind can escape."
" It is believed that black holes form from the collapse of stars. As long as they are emitting heat and light into space, stars are able to support themselves against their own inward gravity with the outward pressure generated by heat from nuclear reactions in their deep interiors. "
"Every star, however, must eventually exhaust its nuclear fuel. When it does so, its unbalanced self-gravitational attraction causes it to collapse. According to theory, if a burned-out star has a mass larger than about three times the mass of our sun, no amount of additional pressure can stave off total gravitational collapse. The star collapses to form a black hole. For a nonrotating collapsed star, the size of the resulting black hole is proportional to the mass of the parent star; a black hole with a mass three times that of our sun would have a diameter of about 10 miles."
"Ironically, Einstein himself did not believe in the existence of black holes, even though they were predicted by his theory."
Big Bang Theory
"Beginning in 1917, Einstein and others applied general relativity to the structure and evolution of the universe as a whole. The leading cosmological theory, called the big bang theory, was formulated in 1922 by the Russian mathematician and meteorologist Alexander Friedmann. Friedmann began with Einstein's equations of general relativity and found a solution to those equations in which the universe began in a state of extremely high density and temperature (the so-called big bang) and then expanded in time, thinning out and cooling as it did so. One of the most stunning successes of the big bang theory is the prediction that the universe is approximately 10 billion years old, a result obtained from the rate at which distant galaxies are flying away from each other. This prediction accords with the age of the universe as obtained from very local methods, such as the dating of radioactive rocks on Earth."
" According to the big bang theory, the universe may keep expanding forever, if its inward gravity is not sufficiently strong to counterbalance the outward motion of galaxies, or it may reach a maximum point of expansion and then start collapsing, growing denser and denser, gradually disrupting galaxies, stars, planets, people, and eventually even individual atoms. Which of these two fates awaits our universe can be determined by measuring the density of matter versus the rate of expansion. Much of modern cosmology, including the construction of giant new telescopes such as the new Keck telescope in Hawaii, has been an attempt to measure these two numbers with better and better accuracy. With the present accuracy of measurement, the numbers suggest that our universe will keep expanding forever, growing colder and colder, thinner and thinner."
All Background information provided by: http://www.pbs.org/wgbh/nova/einstein/relativity/
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The theory of relativity further influenced the law of gravity. Einstein stated that gravity as well as motion can effect time and space. While gravity is pulling a certain direction, the acceleration opposite the object is pulling at the same amount. The closer we are to a huge gravitational mass like the sun the slower time increases. If we had two twins aged 20 and sent one to space and the other left on earth for a 200 year time span, the twin on earth would be long dead as the other returning from space, would have only aged two or so years. Einstein's theory is stating that the Gravity of the sun acts as a life and body preserver in space travel.

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Black holes restrict any light or ways of communication because the mass-gravitational force is so great that nothing can escape. When the star runs out of its nuclear fuel the gravitational pull is so great that it actually collapses on itself. Though his theory was used to discover this, Einstein never actually believed in Black Holes.
Albert Einstein's Theory of Relativity opened a door to one of the most controversial theories in the history of man kind. Einstein's theory shows that a supposed galaxy was expanding at a abnormal rate. The gravitational force of the object was so great that the earth finally started to cool and thin out but the earth still is expanding and may reach it limit on its inward gravity and may collapse on itself.

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General relativity may be the biggest leap of the scientific imagination in history. Unlike many previous scientific breakthroughs, such as the principle of natural selection, or the discovery of the physical existence of atoms, general relativity had little foundation upon the theories or experiments of the time. No one except Einstein was thinking of gravity as equivalent to acceleration, as a geometrical phenomenon, as a bending of time and space. Although it is impossible to know, many physicists believe that without Einstein, it could have been another few decades or more before another physicist worked out the concepts and mathematics of general relativity.